An electric rotating machine that may be used as an electric motor or generator is constituted with a stator and a rotor rotatably disposed on the inside of the stator. When electric current is made to flow through stator windings provided on the stator, heat is generated, which may result in increasing the temperature of the stator and possibly damaging stator parts. For this reason, it is necessary to detect the temperature of the stator at high accuracy. Therefore, techniques of providing a temperature detecting element on the stator and detecting the stator temperature have been conventionally known.
For the purpose of providing a stator of an electric rotating machine in which a temperature of stator windings is detected with quick response and high accuracy, below-listed Patent Document 1 discloses providing a metallic heat transfer part at a neutral point terminal electrically connecting the neutral points of the respective phases of the stator windings, the heat transfer part covering a temperature detecting element.
A configuration according to this conventional art is shown in FIG. 7 at (A) and (B). A terminal base is formed of an insulating resin material, and is disposed on segment conductors 22 at one axial end portion side of the stator. The terminal base is insert molded and integrated with three-phase input terminals and neutral point terminals 50, 54. The neutral point terminal 50 is formed extending along the circumferential direction of the stator core, and includes, at its two end portions in the lengthwise direction, stubs 51 protruding from the terminal base. Between the stubs 51 of the neutral point terminal 50, a cylindrical heat transfer part 52 is provided protruding in the same direction as the stubs 51, while being formed horizontally so that the axis of the cylindrical shape is aligned along the lengthwise direction of the neutral point terminal 50. The first stub 51 of the neutral point terminal 50 is electrically connected, at a neutral point connection part 56, to a lead wire 26 of a winding for one phase among the three-phase stator windings 20. Meanwhile, the other stub 51 of the neutral point terminal 50 and the first stub 55 of the neutral point terminal 54 are electrically connected, at a neutral point connection part 57, to a lead wire 27 of a winding for another phase among the three-phase stator windings 20. Further, the other stub 55 of the neutral point terminal 54 is electrically connected to a lead wire of a winding for the remaining one phase among the three-phase stator windings 20. The neutral point terminals 50 and 54 are electrically connected to each other via a lead wire.
A thermistor 60 serving as a temperature detecting element is inserted into the heat transfer part 52 of the neutral point terminal 50, and is also fitted into a groove 32 in the terminal base. The sensor part 62 of the thermistor 60 is mounted at a position covered by the heat transfer part 52. Further, the thermistor 60 is disposed so that its portion on one side in the lengthwise direction is inserted into the heat transfer part 52, while its portion on the other side in the lengthwise direction is held down by a hook 34 extending from the terminal base and formed in a shape of a claw to cover over the groove 32. In the heat transfer part 52, a slit 53 extending along the lengthwise direction is formed on the side where the stubs 51 are located, which is the inner side in the radial direction of the stator core. The thermistor 60, which is inserted into the heat transfer part 52 and fitted into the groove 32, is covered with an insulating resin material 36 obtained by melting an insulating powder